We make a variety of things including cookies for humans and dogs.
BRCGS doesn't have a problem with it, as long as you meet their requirements.
Here in the USA we have to comply with FDA's Preventive Controls for Animal Food. It's not onerous, as it's basically Preventive Controls for Human Food with some specificity to animal food.
The fact that we only make "treats" or "snacks" for dogs means a lot of the specificity in the Animal Food law does not apply.
The only real difference we have with producing human cookies and dog cookies is that our dog cookie customer(s) require micro testing of the finished product before we can ship it.